Machines and equipment used at many production sites are typically controlled by a control system including, for example, programmable logic controllers (PLCs). The control system uses remote devices installed at separate positions in the field, and provides command values to these remote devices and collect field information from each remote device. The command values and the field information are transmitted with a field network.
The control system includes remote devices with different capabilities. For these remote devices, command values may be updated in periods optimum for their capabilities.
Techniques for transmitting data with networks have been developed to optimize data sequences in the order of priorities in correspondence with bandwidths (e.g., Japanese Unexamined Patent Application Publication No. 2012-094944, or Patent Literature 1).